cache: fix option help text
cache: fix option help text

seuffert/rclone,olihey/rclone,B4dM4n/rclone,ncw/rclone,olihey/rclone,B4dM4n/rclone,yonjah/rclone,yonjah/rclone,ncw/rclone,yonjah/rclone,B4dM4n/rclone,olihey/rclone,B4dM4n/rclone,seuffert/rclone,olihey/rclone,ncw/rclone,ncw/rclone,seuffert/rclone,yonjah/rclone,seuffert/rclone